1. Field of the Invention
The present invention relates to an ink jet ink, an ink jet recording method, an ink cartridge, a recording unit and an ink jet recording apparatus.
2. Related Background Art
An ink jet recording method is such a recording method that minute droplets of ink are applied to a recording medium such as plain paper or glossy medium, thereby forming an image, and is rapidly spread because of low cost and improved recording speed. With rapid spreading of digital cameras in addition to development of high-quality images obtainable by the ink jet recording method, the ink jet recording method is now commonly used as an output method of images comparable with silver halide photography.
In recent years, development of higher-quality images obtained by the ink jet recording method has been further advanced than before due to use of extremely fine ink droplets and improved color ranges attending on introduction of multiple color inks. However, requirements for coloring materials and inks have become greater on the other hand, and there is a demand for higher-level properties for improvement of color developability and reliability such as clogging prevention and ejection stability.
On one hand, the ink jet recording method involves such a problem that the resulting recorded article is poor in image preservability. In general, a recorded article obtained by an ink jet recording method involves such a problem that the image preservability thereof is poor compared with a silver halide photograph. More specifically, when the recorded article is exposed to light, humidity, heat or ozone gas present in the air for a long period of time, such a problem that a coloring material on the recorded article is deteriorated, and so change in color tone of the image or color fading is liable to occur is caused.
A great number of proposals have heretofore been made in order to improve the preservability of an image formed with a yellow ink using a coloring material particularly low in light fastness among coloring materials of various colors. For example, a yellow coloring material capable of forming an image very excellent in ozone gas fastness and light fastness and excellent in color developability has been proposed (see International Publication No. WO 2006/082669).